Many hydrocarbon producing wells around the world, require artificial lift. A common form of artificial lift is gas lift. The purpose of a gas lift system is to introduce gas below the fluid column in order to increase the velocity of the fluid, thereby lifting the fluid to the surface. Gas lift systems typically have several gas injection points along the length of the fluid column in the wellbore.
Typically the production tubing is run inside the cased well preferably terminating just above the perforations in the casing. At the lower end of the production tubing a packer is utilized to seal the lower end of production tubing to the casing. The gas injection points typically consist of side pocket mandrel's with gas lift valves in each side pocket.
With the gas lift system in operation, pressurized gas is supplied to the annular region formed between the exterior of the production tubing and the interior of the casing. The packer at the lower end of the production tubing prevents the pressurized gas from flowing into the formation. Typically the only pathway for the pressurized gas to flow is through the gas lift valves in the side pocket mandrels. As the pressurized gas enters the fluid column through the gas lift valves, the fluid column is lightened by mixing gas with the fluid, increasing the velocity of the fluid as it moves upward in the production tubing thereby lifting fluid out of the well.
Because the pressurized gas is supplied through the annular area between the production tubing and the casing, the pressurized gas supply is typically limited to the area above the packer. Commonly the packer may be set 100 feet above the perforations through the casing. However in some instances, the distance from the packer to the bottom perforations can be quite large, in some cases as much as 1000 feet or more. As the well is depleted, the natural fluid level of the well may be lower than the lowest injection point in the gas lift system thereby rendering the gas lift system virtually useless and thereby rendering the fluid remaining in the well below the packer essentially unrecoverable by current gas lift methods.
The current invention describes an apparatus and method to lower the initial gas lift location to a deeper location within the wellbore that in many instances is below the packer and below the bottom of the production tubular.